Satellite radioterminal communications systems and methods can terrestrially reuse satellite frequencies in an ancillary terrestrial network. Such systems and methods are described, for example, in published U.S. patent application Ser. No. 2003/0073436 A1 to Karabinis et al., entitled Additional Systems and Methods for Monitoring Terrestrially Reused Satellite Frequencies to Reduce Potential Interference, published Apr. 17, 2003, the disclosure of which is hereby incorporated herein by reference in its entirety as if set forth fully herein. As described in this published patent application, a satellite radioterminal system includes a space based component such as a satellite and an Ancillary Terrestrial Network (ATN) that includes a plurality of Ancillary Terrestrial Components (ATC). The space based component is configured to wirelessly communicate with radioterminals, also referred to as “radiotelephones”, in a satellite footprint over a satellite radioterminal frequency band. The ancillary terrestrial network is configured to wirelessly communicate with radioterminals in the satellite footprint over at least some of the satellite radioterminal frequency band, to thereby terrestrially reuse at least some of the satellite radioterminal frequency band.
Satellite radioterminal communications systems and methods that may employ terrestrial reuse of satellite frequencies are also described in U.S. Pat. No. 6,684,057 to Karabinis, entitled Systems and Methods for Terrestrial Reuse of Cellular Satellite Frequency Spectrum; and Published U.S. patent application Ser. Nos. US 2003/0054760 to Karabinis, entitled Systems and Methods for Terrestrial Reuse of Cellular Satellite Frequency Spectrum; US 2003/0054761 to Karabinis, entitled Spatial Guardbands for Terrestrial Reuse of Satellite Frequencies; US 2003/0054814 to Karabinis et al., entitled Systems and Methods for Monitoring Terrestrially Reused Satellite Frequencies to Reduce Potential Interference; US 2003/0054762 to Karabinis, entitled Multi-Band/Multi-Mode Satellite Radiotelephone Communications Systems and Methods; US 2003/0153267 to Karabinis, entitled Wireless Communications Systems and Methods Using Satellite-Linked Remote Terminal Interface Subsystems; US 2003/0224785 to Karabinis, entitled Systems and Methods for Reducing Satellite Feeder Link Bandwidth/Carriers In Cellular Satellite Systems; US 2002/0041575 to Karabinis et al., entitled Coordinated Satellite-Terrestrial Frequency Reuse; US 2002/0090942 to Karabinis et al., entitled Integrated or Autonomous System and Method of Satellite-Terrestrial Frequency Reuse Using Signal Attenuation and/or Blockage, Dynamic Assignment of Frequencies and/or Hysteresis; US 2003/0068978 to Karabinis et al., entitled Space-Based Network Architectures for Satellite Radiotelephone Systems; US 2003/0143949 to Karabinis, entitled Filters for Combined Radiotelephone/GPS Terminals; US 2003/0153308 to Karabinis, entitled Staggered Sectorization for Terrestrial Reuse of Satellite Frequencies; and US 2003/0054815 to Karabinis, entitled Methods and Systems for Modifying Satellite Antenna Cell Patterns In Response to Terrestrial Reuse of Satellite Frequencies, all of which are assigned to the assignee of the present invention, the disclosures of all of which are hereby incorporated herein by reference in their entirety as if set forth fully herein.
Terrestrial reuse of satellite frequencies has recently been authorized by the Federal Communications Commission (FCC). See, REPORT AND ORDER AND NOTICE OF PROPOSED RULEMAKING, FCC 03-15, Flexibility for Delivery of Communications by Mobile Satellite Service Providers in the 2GHz Band, the L-Band, and the 1.6/2.4 Bands, IB Docket No. 01-185, Adopted: Jan. 29, 2003, Released: Feb. 10, 2003, hereinafter referred to as the “FCC Order”. The FCC Order specified that the L-band ATC shall maintain 18 dB of link margin at the edges of its service region in order to achieve in-building penetration and also to suppress radioterminal Effective Isotropic Radiated Power (EIRP), using closed-loop power control, when the radioterminal is radiating outside of signal attenuating structures.
Conventional uplink power control techniques can reduce a radioterminal's EIRP to significantly below a maximum, when a radioterminal is communicating with an ATC in an area of low signal attenuation (i.e., outside of a building). Thus, the potential for interference to satellite systems that may use the same frequencies as the ATC can be reduced or minimized. Moreover, when the radioterminal is inside of a signal attenuating structure such as a building, conventional uplink power control techniques may allow the uplink transmit power to increase and even attain a maximum, so as to overcome the additional penetration loss of the signal attenuating structure. This can be acceptable in terms of interference to co-channel satellites since, by definition, the signal attenuating structure in conjunction with closed-loop power control can ensure, relative to the co-channel satellite system, a level of interference signal suppression approximately equal to the return link (uplink) margin provided by the ATC (e.g., 18 dB).